This invention relates to laser radiation reflected from a microscopically rough target surface and, more particularly, to the elimination of the undesirable phenomenon related thereto which is known as speckle. The term speckle as used herein means, as it does in the art, the phenomenon in which the scattering of light from a highly coherent source (such as a laser) by a rough surface (or an inhomogeneous medium) generates a random-intensity distribution of light that gives the surface (or the medium) a granular appearance, with resultant significant loss of definition of the surface (or of the medium).
More specifically, laser light, reflected from a distant target whose surface roughness exceeds the wavelength of the laser light, produces nulls and lobes (i.e., speckle) in the detector plane which render target definition difficult or impossible. In fact, in a narrow field of view (e.g., telescope in the detector plan) nulls can be wide enough so that a target goes undetected. As will be shown and discussed later herein, studies show a high probability of such an occurrence.
Accordingly, it is fair and accurate to state that what is needed in the art, and is not presently available, is a simple and reliable means of eliminating the aforementioned speckle.